Like all other creatures on earth hominids adapted to their environment through physiological change. But, at a certain point, they began to adapt by means of culture. They were, therefore, an entirely new type of creature--possessing capabilities that had not existed before. Rather than undergoing a few small adaptations that took place over the course of hundreds of thousands of years, these new creatures engaged in continuous adaptation via culture. Their cultures were not static over very long periods. To the extent that new circumstances required additional adaptations they were capable of making them and, to the extent that new adaptations proved superior to previous versions, they were capable of replacing the old with the new. The archaeological study of the prehistoric emergence of the cultural animal has led to the classification of prehistory in terms of periods defined by very broad cultural adaptations. Seven of the broadest of these periods (beginning with the oldest) are known as the Lower Paleolithic, Middle Paleolithic, Upper Paleolithic, Mesolithic, and Neolithic eras and the Bronze and Iron Ages. Each classification involved thousands of years of human cultural adaptation and is characterized by the general development of new technologies (or improvements on older ones) and the development of new forms of social organization.
Lower Paleolithic is the term applied to the culture of Homo erectus, a species that probably evolved by at least 1.8 million years ago and which, by one million years ago, was the only surviving hominid. H. erectus flourished in Africa, Asia and, perhaps, Europe until approximately 500,000 years ago. Over this very long span of time and broad area there was a great deal of variation among H. erectus. By the time H. erectus began to settle in temperate zones it had already "mastered the necessary hunting and foraging strategies to survive in much more diverse environments" than t...